1. Field of the Invention
The present invention relates to an improvement of a digital shutter time control device for digitally controlling a shutter time of a camera which is manually set.
2. Description of the Prior Art
Heretofore, in a digital shutter time control device, such a system has been proposed in the Japanese Laid-Open patent application Sho No. 54-27427 that voltages obtained by operating an object brightness, a film sensitivity and a lens aperture value, etc. are converted to digital values of n bits (out of said n bits, lower level K bits are used for intermediate shutter times, and K+1 to n bits are used for so-called nominal (regular) shutter times with respective step), and one step is further divided into 1/2k steps for providing an automatic exposure control, while at a time of a manual operation exposure information voltages being manually set are converted to digital values then lower level K bits out of said digital values are nullified, so that an accuracy in an actual manual shutter control will not be lowered even an accuracy in the exposure information voltage being manually set is lowered. However, as intermediate shutter times are simply discarded at a time of manual operation in said system, it has such shortcoming that only errors in the positive direction of voltage corresponding to a manually set shutter time is allowed but errors in the negative direction can not be allowed.